The present invention relates to an improved composite gearwheel structure to control the advancement of gripper-carrying straps in weaving looms.
It is known that modern weaving machines are frequently faced--due to the very high speeds and the consequent strong inertias involved--with fairly serious problems in respect of wear of the gripper-carrying straps and of the gearwheels controlling their to-and-fro movements inside the shed. These problems have been addressed for some time, mainly through a careful study of the geometries of the gearwheel teeth and of the strap slits engaging therewith on either side, and by appropriate choices of the materials used for producing the gearwheels and the gripper-carrying straps. In spite of this, the solutions adopted so far are not fully satisfactory, as the wears are still very great.
At present, gearwheels--requiring dimensional stability, wear resistance, lightness and high rigidity--are produced with light alloys or with synthetic plastic materials of various types, while the straps are generally produced as composite structures, obtained by associating laminated plastic with rolled sections.
On the other hand, composite structures for the gearwheels controlling the advancement of gripper-carrying straps have never been studied or realized.